I have a 10 HP Briggs (28B707) in a rear engine Toro. It was running fine then started to loose power and after shutting it off it would not start. Now its blowing air out of the carburetor. Applied air pressure to the cylinder at TDC and air comes out of the intake. Pulled off the head. Put a flash light into the intake port and can see light around the intake valve seat. The intake valve opens as it should on the intake stroke but doesn't completely close on the compression stroke until the piston is at TDC. Since the exhaust valve seems to be working ok and the camshaft is driven by a gear on the crankshaft, why would the intake valve not be closing properly?
Blowing compression out of carburetor. 10HP 28B707
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shiftsuper175607
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Did you check the valve clearances?
Boobala
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Check your engine breather operation, also this manual may be helpful..........
https://drive.google.com/file/d/0B6NaqjIxWV1ycG8wd0s3Z2Q2X00/view
https://drive.google.com/file/d/0B6NaqjIxWV1ycG8wd0s3Z2Q2X00/view
bertsmobile1
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You adjust the valve lash by either grinding some metal off the end of the valve stem to open it up or grinding the valve seat to close it down.
Grinding in these cases is done with wet stones not your angle grinder.
Tinkerer200
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Sounds to me like the valve seat may be loose in block. Unusual for the Intake to do that. IF that is the case and the block isn't badly wallowed out, the seat can be peened back into place per instructions found in the Service Manual for this engine. First you might want to remove the valve (tappet) cover and make sure that the Intake Valve Keeper has not come off. I think you were given a link for a manual IF you have a problem finding what you want, I can send you a Service Manual.
Walt Conner
wconner5 at frontier dot com
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Check post #4 Walt, ... I already sent him the Manual ...... Boo
Took the intake valve out and ground down the end to get proper clearance. Went to do the exhaust valve and found it was easier to just push the valve off of the tappet with a screw driver and file the end of the valve stem. Runs great now. Thanks for all the help.